A PRELIMINARY-STUDY ON THE ULTRASTRUCTURE OF ACTINOMADURA-PELLETIERI AND ITS HOST TISSUE REACTION

This is the first report on the tine structure of Actinomodura pelleti eri. The in vitro ultrastructure of the organism and that of the grain in vivo were similar. The grain consisted of packed filaments with a faintly electron-dense matrix in between. The individual filament was septate, the cytoplasm was either vacuolated or contained intracellula r organelles and the cytoplasmic membrane was adherent to the filament ous wall, which has three electron-dense and two electron-lucent layer s. The absence of cement substance around the grain may partially expl ain the aggressive and destructive behaviour of this organism and may probably also explain its good response to medical treatment. The infl ammatory host reaction was similar to that seen with all mycetoma orga nisms except that there was a massive neutrophil reaction. This was co nfirmed by electron microscopy.